Conventionally, there has been known a radar device for vehicles, which is mounted in an own vehicle, for detecting an object approaching the own vehicle from the front direction or a lateral direction. Specifically, the radar device for vehicles detects an object approaching the own vehicle by using a milliwave radar. The radar device for vehicles determines, based on the detection result, a risk of collision between the own vehicle and the object. Further, the radar device for vehicles provides, when it has determined that there is a risk of collision between the own vehicle and the object, a reminder to the driver by means of an alarm device or the like which is provided in the own vehicle.
A general radar device for vehicles recognizes each object approaching an own vehicle from the front direction or a lateral direction as a dot. Accordingly, the type of the object (for example, a vehicle, a bicycle, a pedestrian, or the like) cannot be identified.
As a technology that solves the above problem, there is an apparatus disclosed in Patent Literature 1. The apparatus disclosed in Patent Literature 1 detects objects by means of a radar provided in an own vehicle, and collects objects which are close to one another from among the detected objects as a connected body. Then, when both a moving speed and a moving direction of the connected body are within respective predetermined ranges, the connected body is identified as a pedestrian, a bicycle, or a wheelchair.    [Patent Literature 1] Japanese Laid-Open Patent Publication No. 2006-160116